The Blue Jays were part of the American League's 1976-1977 expansion, joining the Junior Circuit with the Seattle Mariners for the 1977 season.

They became the second Canadian franchise, joining the Montreal Expos.

After struggling through the late 1970s, they laid the foundation for a contending team in the early 1980s with the arrival of Lloyd Moseby, George Bell, Jesse Barfield, Dave Steib, and other young players.

By 1983 they were a bona fide contender, and in 1985 they won their first AL East title.

The theme for the rest of that decade was disappointment; the Jays losing the 1987 division title on the final day of the season to Detroit and failing to advance to the World Series in 1989 when they lost to the A's in the LCS.

Manager Cito Gaston melded home-grown talent with veteran stars Dave Winfield, Rickey Henderson, Paul Molitor, and Jack Morris, winning World Series titles in 1992 and 1993, and a division title in 1991. For a few seasons the team "north of the border" sat on top of the baseball world.

Age and free agency cost the Jays some of their stars, and by 1995 they were back in the middle of the pack in the American League East. The later part of the 1990s saw the team building around young stars Jose Cruz Jr., and Carlos Delgado.

In 2004 the Toronto Blue Jays finished in 5th place in the American League East Division with a 67-94.